Heating cooker

ABSTRACT

Cooking is performed to serve tasty food by appropriately managing moisture of an object to be cooked without burning the surface thereof. A box-shaped housing, a cooking cavity for accommodating an object to be cooked, the cooking cavity being arranged within the housing, an upper-face heater and a lower-face heater arranged in the cooking cavity, a boiler arranged within the cooking cavity, a water tray formed outside the cooking cavity and into which a given amount of water that is entirely evaporated in a given steaming time is poured, a water guide passage within the housing, the water guide passage into which water is supplied from the water tray to the boiler; and a control unit for causing an operation to generate steam from the boiler to be performed for at least a steaming time from when cooking starts are provided.

This is a Continuation of application Ser. No. 15/541,219 filed Jun. 30,2017, which in turn is a National Phase of International PatentApplication No. PCT/JP2016/051793 filed Jan. 22, 2016, which claimspriority to Japanese Patent Application No. 2015-011474 filed Jan. 23,2015. The disclosures of the prior applications are hereby incorporatedby reference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a heating cooker that supplies steamwhen cooking, with heat, an object to be cooked, such as bread.

BACKGROUND ART

Known heating cookers include those using only a heater, and those usinga steam generator (such as a boiler) in addition to a heater (see PatentDocuments 1 to 3). Cooking methods in which steam is added duringheating depending on the object to be cooked are also known.

CITATION LIST Patent Document

Patent Document 1: JP H07-055155A

Patent Document 2: JP H08-128653A

Patent Document 3: JP 2014-023801A

SUMMARY OF INVENTION Technical Problem

The aforementioned heating cookers have the following problems. That isto say, when cooking toast, which is main usage of those heatingcookers, moisture that is originally contained in bread, such as a sliceof square bread, evaporates during cooking, and the texture and tastethereof is lost. Also, as in the case where a savory smell comes fromthe toaster during cooking, the smell of butter contained in the breadalso escapes to the air with the evaporation of the moisture, and theflavor is significantly lost.

Furthermore, dressed bread, croissants, and the like are burnt on theirsurface before being heated to the inside, and there has been no methodfor optimally heating these kinds of bread.

Also, a water tank is necessary to supply water to a boiler. If thewater in the tank is not used up, or the water remains in the boiler,the tank needs to be cleaned or the water needs to be drained forhygiene, which takes time and effort.

The present invention aims to provide a heating cooker that is capableof perform cooking to serve tasty food by appropriately managingmoisture of an object to be cooked without burning the surface thereof.

The present invention also aims to provide a heating cooker that has asteam function and is capable of performing cooking while appropriatelymaintaining a hygienic state of an object to be cooked by using up allwater.

Solution to Problem

To solve the foregoing problems and achieve the above-stated objects, aheating cooker according to the present invention is configured asfollows.

A box-shaped housing; a cooking cavity for accommodating an object to becooked, the cooking cavity being arranged within the housing; a heaterarranged within the cooking cavity; a steam generator arranged withinthe cooking cavity; a water tray into which a given amount of water ispoured, the given amount of water being entirely evaporated within thegiven steaming time; a water guide passage for supplying the water fromthe water tray to the steam generator; and a control unit for causing anoperation to generate steam from the steam generator to be performed forat least the steaming time from when cooking starts, are provided.

Advantageous Effects of Invention

According to the present invention, cooking can be performed to servetasty food by appropriately managing moisture of an object to be cookedwithout burning the surface thereof. Also, the steam function isprovided but no water tank is necessary, and cooking can be performedwhile appropriately maintaining a hygienic state of an object to becooked by using up the water.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a heating cooker according to afirst embodiment of the present invention.

FIG. 2 is an illustrative diagram showing an internal structure of theheating cooker.

FIG. 3 is an illustrative diagram showing a control device in theheating cooker.

FIG. 4 is an illustrative diagram showing a heating cooking flow of theheating cooker.

FIG. 5 is an illustrative diagram showing exemplary control in a cookingmode in the heating cooking flow.

FIG. 6 is an illustrative diagram showing another example of a cookingmode in the heating cooking flow.

FIG. 7 is a perspective view showing main part of a heating cookeraccording to a second embodiment of the present invention.

FIG. 8 is an illustrative diagram showing a heating cooking flow of theheating cooker according to the second embodiment of the presentinvention.

FIG. 9 is a perspective view showing main part of a heating cookeraccording to a third embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a perspective view showing a heating cooker 10 according tothe first embodiment of the present invention. FIG. 2 is an illustrativediagram showing an internal structure of the heating cooker 10. FIG. 3is an illustrative diagram showing a control unit 100 in the heatingcooker 10. FIG. 4 is an illustrative diagram showing a heating cookingflow of the heating cooker 10. FIG. 5 is an illustrative diagram showingan example of a cooking mode in the heating cooking flow. FIG. 6 is anillustrative diagram showing another example of a cooking mode in theheating cooking flow.

The heating cooker 10 includes a rectangular parallelepiped, box-shapedhousing 11, a rectangular parallelepiped cooking cavity 20 that isarranged within the housing 11 and accommodates an object to be cooked,a heater unit 30 arranged within the cooking cavity 20, a boiler (steamgenerator) 40 arranged within the cooking cavity 20, and a control unit100 for controlling operations of the heater unit 30 and the boiler 40.

A door 12 is provided in a front face of the housing 11, and anoperation unit 13 is provided in a front face of this door 12. Theoperation unit 13 is provided with an input portion 14 for setting aheating time and switching a cooking mode, and a notifying portion 15,such as an LED or a buzzer.

A water tray 21 is provided in an upper portion of the cooking cavity20. A water guide passage 50 for guiding water W from the water tray 21to a later-described boiler container 41 is provided in the housing 11.The water guide passage 50 includes a first guide portion 51 that guidesthe water W in an obliquely downward direction from the bottom of thewater tray 21 toward an upper portion of an outer face of the cookingcavity 20, and a second guide portion 52 that guides the water W fromthe upper portion towards the lower portion of the outer face of thecooking cavity 20 in a vertical direction to the boiler container 41.

The water tray 21 can accommodate a given amount (e.g. 10 cc) of waterW, and is formed to be capable of receiving the given amount of water Wcontained in a measuring cup M without being flooded, and causing thewater W to flow into the water guide passage 50. The given amount isdetermined to be an amount that can be entirely evaporated in a givensteaming time (e.g. 1 minute) when a later-described boiler heater 42 isenergized.

A metal grill grid 22, on which an object to be cooked is placed, isprovided substantially horizontally at the middle of the cooking cavity20. Furthermore, an in-cavity thermistor (temperature sensor) 24 isprovided within the cooking cavity 20.

The heater unit 30 includes an upper-face heater 31 arranged in an upperportion of the cooking cavity 20, and a lower-face heater 32 arranged ina lower portion.

The boiler 40 includes the boiler container 41 formed in a plate shapeand located below the grill grid 22, the boiler heater 42 for heatingthe boiler container 41, and a boiler thermistor (temperature sensor) 43attached to the boiler container 41. The capacity of the boilercontainer 41 is greater than or equal to a given amount (e.g. 10 cc).

The control unit 100 includes a control device 110 for giving operationinstructions, and performing calculation and detection according toprograms for executing a heating cooking flow shown in FIG. 4 , forexample, and a power supply device 120 for independently energizing theupper-face heater 31, the lower-face heater 32, and the boiler heater42.

The control device 110 receives input from the in-cavity thermistor 24and the boiler thermistor 43 and input from the input portion 14, andmakes output to the notifying portion 15 and output to the power supplydevice 120. The control device 110 also causes an operation to generatesteam from the boiler container 41 to be performed for at least a givensteaming time (e.g. 1 minute) from when cooking starts.

The power supply device 120 is provided with a first relay 121, a secondrelay 122, and a third relay 123 that are connected to the upper-faceheater 31, the lower-face heater 32, and the boiler heater 42,respectively.

The thus-configured heating cooker 10 performs heating cooking asfollows. Initially, the door 12 is opened, and a given amount (10 cc) ofwater W is poured into the water tray 21. The given amount can easily bepoured by pouring water using a measuring cup with a predeterminedcapacity (10 cc). The water W poured in the water tray 21 is guided tothe boiler container 41 through the water guide passage 50. Next, anobject to be cooked, such as a slice of square bread, is placed on thegrill grid 22, and the door 12 is closed.

For cooking settings, a cooking mode is selected (ST10), and a timer isset (ST 11). When setting the timer, any time from 1 minute at shortestup to 15 minutes at longest can be set to adjust the degree of browningthe object to be cooked. Thus, heating cooking starts (ST12), and boilercontrol and heating control are performed.

In boiler control, the third relay 123 operates first, and the boilerheater 42 is energized (ST20). As a result, the water W in the boilercontainer 41 is heated and evaporated, and the steam fills the cookingcavity 20. The steam enfolds the object to be cooked, making itdifficult for the moisture in the object to be cooked to evaporate. Notethat the temperature at the boiler thermistor 43 does not exceed 100° C.in a state where the water

W remains After the water W has entirely evaporated and run out, thetemperature in the boiler container 41 rapidly increases. When thetemperature at the boiler thermistor 43 reaches or exceeds 120° C.(ST21), it is determined that the water W has run out. The controldevice 110 opens the third relay 123 in the power supply device 120 tostop energizing the boiler heater 42 (ST23).

If the temperature at the boiler thermistor 43 does not exceed 120° C.,it is measured whether or not 1 minute has passed (ST22). The flowproceeds to ST23 if 1 minute has passed, and returns to ST21 if not.

In heating control, the first relay 121 and the second relay 122 areoperated in a heating pattern corresponding to a selected cooking modeto energize the upper-face heater 31 and the lower-face heater 32, andheating cooking starts (ST30). FIGS. 5 and 6 show exemplary heatingpatterns.

After the elapsed time from when heating started has reached the timeset to the timer (e.g. 10 minutes) (ST31), energization of theupper-face heater 31 and the lower-face heater 32 is stopped (ST32), andheating cooking ends.

As described above, with the heating cooker 10 according to thisembodiment, a predetermined given amount of water W can be entirelyevaporated within a given time from when cooking starts. Accordingly, nowater W remains after the heating cooking. Also, since a small amount ofwater W is required for heating cooking, water need only be suppliedevery time cooking is performed, and no water tank is necessary.Accordingly, water W is always new and hygienic.

Regarding the object to be cooked, it is possible to prevent moisturefrom escaping from the object to be cooked and suppress oxidation of theobject to be cooked to make the texture of the surface thereof crispyand make the object to be cooked tasty through cooking, by supplyingsteam in first 1 minute or so and thereafter heating the object to becooked, rather than continuously supplying steam during cooking orsupplying steam at the last stage of cooking. For this reason, thisheating cooker is suitable for objects to be cooked such as croissants.

Furthermore, in the case of an object to be cooked such as toast,moisture that is originally contained in the bread is not evaporatedduring cooking, and the texture and taste thereof are not lost. Thesmell of butter contained in the bread is not lost with the evaporationof the moisture either, and the flavor can be maintained. In addition,there has been no method to optimally heat dressed bread, croissants,and the like since the surface thereof is burnt before being heated tothe inside. However, the heating cooker 10 can heat the bread to theinside without burning the surface thereof.

FIG. 7 is a perspective view showing a heating cooker 10A according tothe second embodiment of the present invention with a door 12 removed.FIG. 8 is an illustrative diagram showing a heating cooking flow of theheating cooker 10A. Note that, in FIG. 7 , the same functional portionsas those in FIGS. 1 and 2 are assigned the same signs, and detaileddescriptions thereof will be omitted.

The heating cooker 10A includes a rectangular parallelepiped, box-shapedhousing 11, a rectangular parallelepiped cooking cavity 20A that isarranged within the housing 11 and accommodates an object to be cooked,a heater unit 30 arranged within the cooking cavity 20A, a boiler (steamgenerator) 40A arranged next to the cooking cavity 20A, and a controlunit 100A for controlling operations of the heater unit 30 and theboiler 40A.

The cooking cavity 20A is provided with a water tank 200 with a capacityof 1000 cc, for example, and a water supply valve 210 provided below thewater tank 200, in place of the water tray 21 and the water guidepassage 50.

The water supply valve 210 is configured to be able to measure a givenamount (e.g. 10 cc) of water W and supply the water W to a boilercontainer 41. The given amount is determined to be an amount that can beentirely evaporated in a given steaming time (e.g. 1 minute) when alater-described boiler heater 42 is energized.

The boiler 40 is provided below the water tank 200, and includes theboiler container 41, the boiler heater 42 for heating the boilercontainer 41, and a boiler thermistor (temperature sensor) 43 attachedto the boiler container 41. The capacity of the boiler container 41 isgreater than or equal to a given amount (e.g. 10 cc).

A control unit 100A has a function of giving operation instructions, andperforming calculation and detection according to programs for executinga heating cooking flow shown in FIG. 8 , for example.

The thus-configured heating cooker 10A performs heating cooking asfollows. Initially, the door 12 is opened, and water W of an amount(e.g. 800 cc) that is close to the upper limit of the capacity of thewater tank 200 is poured into the water tank 200. Next, an object to becooked, such as toast (a piece of square bread), is placed on the grillgrid 22, and the door 12 is closed.

For cooking settings, a cooking mode is selected (ST40), and a timer isset (ST41). When setting the timer, any time from 1 minute at shortestup to 15 minutes at longest can be set to adjust the degree of browningthe object to be cooked. Thus, heating cooking starts (ST42), and boilercontrol and heating control are performed.

In boiler control, the water supply valve 210 is opened (ST50), a givenamount (e.g. 10 cc) of water W corresponding to a cooking mode issupplied from the water tank 200 to the boiler container 41 (ST51), andthe water supply valve 210 is closed (ST52). The boiler heater 42 isthen energized (ST53), and thus the water W in the boiler container 41is heated to become steam, and blows into the cooking cavity 20A. Thesteam enfolds the object to be cooked, making it difficult for themoisture in the object to be cooked to evaporate. Note that thetemperature at the boiler thermistor 43 does not exceed 100° C. in astate where the water W remains. After the water W has entirelyevaporated and run out, the temperature in the boiler container 41rapidly increases. When the temperature at the boiler thermistor 43reaches or exceeds 120° C., it is determined that the water W has runout (ST54), and energization of the boiler heater 42 is stopped (ST56).

If the temperature at the boiler thermistor 43 does not exceed 120° C.,it is measured whether or not the time set in the cooking mode haspassed (ST55). If the time set in the cooking mode has passed, the flowproceeds to ST56.

Heating control is the same as that in the above-described heatingcooker 10, and a description thereof will be omitted.

As described above, with the heating cooker 10A according to thisembodiment, a predetermined given amount of water W can be entirelyevaporated in a given time, and accordingly, no water W remains afterthe heating cooking. Also, since water W required for heating cooking issupplied using the water supply valve 210 in accordance with the cookingmode, it is not necessary to supply water every time cooking isperformed. Furthermore, the necessary amount of water W can be adjustedin accordance with the cooking mode, and a change in the size or type ofan object to be cooked can be dealt with.

Regarding the object to be cooked, it is possible to prevent moisturefrom escaping from the object to be cooked and suppress oxidation of theobject to be cooked to make the texture of the surface thereof crispyand make the object to be cooked tasty through cooking, by supplyingsteam in first 1 minute or so and thereafter heating the object to becooked, rather than continuously supplying steam during cooking orsupplying steam at the last stage of cooking. For this reason, thisheating cooker is suitable for objects to be cooked such as croissants.

In addition, the same effects as those of the heating cooker 10 can beachieved.

FIG. 9 is a perspective view showing a heating cooker 10B according tothe third embodiment of the present invention with a door 12 removed. InFIG. 9 , the same functional portions as those in FIG. 7 are assignedthe same signs, and detailed descriptions thereof will be omitted.

The heating cooker 10B is provided with a boiler 40 above a water tank200. The heating cooker 10B can also perform heating cooking similar tothe heating cooker 10A, and can achieve the same effects as those of theheating cooker 10A.

Note that the present invention is not limited to the above-describedembodiments. For example, although the above example uses the boiler 40as a steam generator, steam may be generated using an ultrasonicgeneration device. The configuration or the like of the heater unit 30may be changed as appropriate in accordance with the size and shape ofthe cooking cavity 20, the type of an object to be cooked, or the like.Furthermore, although the given steaming time is set to 1 minute, it isnot limited to this time, and may be changed as appropriate inaccordance with the size of the cooking cavity 20, the type of an objectto be cooked, or the like. Of course, the present invention may bemodified and implemented in various manners without departing from thegist of the invention.

LIST OF REFERENCE NUMERALS

-   -   10, 10A, 10B Heating cooker    -   11. Housing    -   12 Door    -   13 Operation unit    -   14 Input portion    -   15 Notifying portion    -   20, 20A Cooking cavity    -   21 Water tray    -   22 Grill grid    -   24 In-cavity thermistor (temperature sensor)    -   30 Heater unit    -   31 Upper-face heater    -   32 Lower-face heater    -   40 Boiler (steam generator)    -   41 Boiler container    -   42 Boiler heater    -   43 Boiler thermistor (temperature sensor)    -   50 Water guide passage    -   100 Control unit    -   110 Control device    -   120 Power supply device    -   200 Water tank    -   210 Water supply valve    -   W Water

The invention claimed is:
 1. A toaster comprising: a box-shaped housingwith a cooking cavity for accommodating an object to be cooked; a watertray at an upper portion of the housing, wherein the water tray isconfigured to have water poured therein; a heater in the housing andconfigured to heat the object to be cooked; a steam generator in thehousing and configured to feed steam into the cooking cavity; a waterguide passage in the housing and configured to guide the water pouredinto the water tray to the steam generator; a control unit in thehousing and configured to control operations of the heater and the steamgenerator; and a door for the cooking cavity that exposes the water trayand allows the water be poured into the water tray when the door isopen, wherein the door is in a front face of the housing, and the watertray has an opening that faces, and is accessible through, a top face ofthe housing.
 2. The toaster according to claim 1, wherein the door has alower end portion attached to the housing, and is openable and closable.3. The toaster according to claim 1, wherein the water tray is in afront part of the top face of the housing.
 4. The toaster according toclaim 1, wherein a portion of the door is configured to cover theopening by extending along the top face when the door is in a closedposition.